An equilateral triangle abc prism rests on a table. A light ray makes an incident angle of B at the ab surface. The index of refraction of the prism is 1.5. What is the smallest angle of B, for which the light ray will exit from the bc surface? Unit of B is in degree. 60 a C O 21b 60 B a C O 21 O 15 0 9 O 45 O 32 O 28A light beam strikes a piece of glass with an incident angle of 450. The beam contains two colors: 600 nm and an unknown wavelength. The index of refraction for the 600-nm light is 1.8. Assume the glass is surrounded by air, which has an index of refraction of 1. What is the index of refraction nu for the unknown wavelength if its refraction angle is 70 smaller than that of the 600 nm light. O 2.8 O 1.9 O 1.4 O 2.5 O 2.2 O 1.7